Controlling Water Clover (Marsilea) in Ponds

Water clover (Marsilea quadrifolia) resembles four-leaf clover and spreads aggressively in shallow water. Two aquatic herbicides provide effective control.

Approved Treatments

• Diquat (Reward, others) — contact herbicide, fast-acting, no soil residual.
• Rodeo (glyphosate for aquatic use) — systemic, kills roots, requires surfactant approved for aquatic sites.

Application Tips

1. Treat early in growth cycle for best uptake.
2. Follow label rates exactly—overdosing risks fish kill from oxygen depletion.
3. Treat ⅓–½ of pond at a time if heavy infestation.
4. Re-treat as needed; spores and rhizomes persist.

Note

Only use herbicides labeled for aquatic sites. Terrestrial formulations contain surfactants toxic to fish and amphibians.